How to make particles refract/change direction through an object
you need to use keyed physics in particle system,then use a curve of your desired shape as the guide for leading the particles,here's how you do;


create a particle system,crank up the lifetime and play around with
emitter geometry.
Create a curve of desired shape.
Create another particle system at the end of the curve.
In physics tab,select Newtonian,then add keys and select the target.


Voila there you go.